[thristian]

Yes it was, in 1991 when NT and Java and Cocoa were new or under development. In 1996, Unicode 2.0 came out with surrogate pairs and astral planes, and Unicode was no longer a 16 bit encoding.

I'm pretty sure work on V8 started after 1996.

More likely is the idea that the authors of V8 felt that UCS-2 was an acceptable speed/correctness trade-off.